[Caitlin]

What size thread are you using?
Maybe going up a little in size will do it. Here is my trick for checking the hole size with the knot size. I take a doubled thread on a needle and pass it through the bead. Pass the needle back thorough the bead and pull. If it goes through, the thread is the right size for those beads. To check if the thread is too small, tie an overhand knot and push the bead over it. If it goes over, the thread is too small.

Some posters do like to use 4- 6 even 8 strands, so the thread needs to be small for that to work.

I like to use a needle with a doubled thread. I string two or three beads and attach the clasp then go back and knot. (There are whole threads about this subject on this forum.)

After the clasp is attached string the rest of the beads/pearls on and proceed to knot them between each pearl with a simple overhand knot. When the knot is seated, separate the two threads and pull. Even if the knot is a centimeter off it will slide into place.

There is a technique to flipping the beads though the overhand knot loop on each overhand knot. If you do it very close to the last pearl pushed up against the already knotted ones, the knot will be in the correct place. Still, separate and pull the threads to really snuggle it in there. I also give a pull of the strung bead each time to be sure there are no kinks. if there are, another tug of the twp threads will unloose the kink.

I also recommend you use actual beading thread. A trip to a bead store is a good idea. there are a couple of other tools to make your job easier. They are on the Tool Thread.You can buy a little spool of Nymo in almost any color for just $2-3 for your first tries. Buy in a small, medium and large size depending on the size of the holes in your pearls and or gemstones. Often the pearls have a larger hole than the gemstones. Smaller pearls have smaller holes.

If you buy silk on a card, make sure it does not have a needle attached. The one string knotting method is hard to master and really quite unnecessary to use. Buy beading needles. The twisted wire ones come in thin medium and thick.

Check out the stickys on the Lowly Beader's Forum for much more detail.
Happy knotting!